[PATCH v2 1/3] perf record: Fix per-thread option.

Ian Rogers
2022-04-14T01:46:51Z

From: Alexey Bayduraev <alexey.bayduraev@gmail.com>

Per-thread mode doesn't have specific CPUs for events, add checks for
this case.

Minor fix to a pr_debug by Ian Rogers <irogers@google.com> to avoid an
out of bound array access.

Reported-by: Ian Rogers <irogers@google.com>
Fixes: 7954f71689f9 ("perf record: Introduce thread affinity and mmap masks")
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Alexey Bayduraev <alexey.bayduraev@gmail.com>
---
tools/perf/builtin-record.c | 22 +++++++++++++++++-----
1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index ba74fab02e62..069825c48d40 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -989,8 +989,11 @@ static int record__thread_data_init_maps(struct record_thread *thread_data, stru
struct mmap *overwrite_mmap = evlist->overwrite_mmap;
struct perf_cpu_map *cpus = evlist->core.user_requested_cpus;

- thread_data->nr_mmaps = bitmap_weight(thread_data->mask->maps.bits,
- thread_data->mask->maps.nbits);
+ if (cpu_map__is_dummy(cpus))
+ thread_data->nr_mmaps = nr_mmaps;
+ else
+ thread_data->nr_mmaps = bitmap_weight(thread_data->mask->maps.bits,
+ thread_data->mask->maps.nbits);
if (mmap) {
thread_data->maps = zalloc(thread_data->nr_mmaps * sizeof(struct mmap *));
if (!thread_data->maps)
@@ -1007,16 +1010,17 @@ static int record__thread_data_init_maps(struct record_thread *thread_data, stru
thread_data->nr_mmaps, thread_data->maps, thread_data->overwrite_maps);

for (m = 0, tm = 0; m < nr_mmaps && tm < thread_data->nr_mmaps; m++) {
- if (test_bit(cpus->map[m].cpu, thread_data->mask->maps.bits)) {
+ if (cpu_map__is_dummy(cpus) ||
+ test_bit(cpus->map[m].cpu, thread_data->mask->maps.bits)) {
if (thread_data->maps) {
thread_data->maps[tm] = &mmap[m];
pr_debug2("thread_data[%p]: cpu%d: maps[%d] -> mmap[%d]\n",
- thread_data, cpus->map[m].cpu, tm, m);
+ thread_data, perf_cpu_map__cpu(cpus, m).cpu, tm, m);
}
if (thread_data->overwrite_maps) {
thread_data->overwrite_maps[tm] = &overwrite_mmap[m];
pr_debug2("thread_data[%p]: cpu%d: ow_maps[%d] -> ow_mmap[%d]\n",
- thread_data, cpus->map[m].cpu, tm, m);
+ thread_data, perf_cpu_map__cpu(cpus, m).cpu, tm, m);
}
tm++;
}
@@ -3329,6 +3333,9 @@ static void record__mmap_cpu_mask_init(struct mmap_cpu_mask *mask, struct perf_c
{
int c;

+ if (cpu_map__is_dummy(cpus))
+ return;
+
for (c = 0; c < cpus->nr; c++)
set_bit(cpus->map[c].cpu, mask->bits);
}
@@ -3680,6 +3687,11 @@ static int record__init_thread_masks(struct record *rec)
if (!record__threads_enabled(rec))
return record__init_thread_default_masks(rec, cpus);

+ if (cpu_map__is_dummy(cpus)) {
+ pr_err("--per-thread option is mutually exclusive to parallel streaming mode.\n");
+ return -EINVAL;
+ }
+
switch (rec->opts.threads_spec) {
case THREAD_SPEC__CPU:
ret = record__init_thread_cpu_masks(rec, cpus);
--
2.36.0.rc0.470.gd361397f0d-goog